Forum home› Garden design
This Forum will close on Wednesday 27 March, 2024. Please refer to the announcement on the Discussions page for further detail.

Waterproof membrane for shed

emma louemma lou Posts: 170
in Garden design
We are just laying the base for a treated shed. However, the garden is on a slight incline and two sides of the shed are sat slightly lower than the ground level (by a few inches). Do I need to put down a membrane and also, if so, do I need to put this down before I lay the sand or between the sand and the slabs? Many thanks.

Posts

  • Jenny_AsterJenny_Aster Posts: 945
    I would say definitely use a membrane, putting it down under the layer of sand. 
    Trying to be the person my dog thinks I am! 

    Cambridgeshire/Norfolk border.
  • nick615nick615 Posts: 1,487
    I agree with Jenny, but avoid walking on the membrane as anything sharp can puncture it and allow damp to come through?  I suppose sand - membrane - sand - slabs could be best.
  • KT53KT53 Posts: 9,016
    Best solution would be to dig down to about 6" below the level of the shed on those sides to create a trench 6 to 12 inches wide and fill that with gravel to improve drainage. It will also ensure that the soil doesn't come into contact with the shed.  Even a small tear in a waterproof membrane will end up having the opposite effect to that desired, as it will let the water through and then hold it against the timber, causing it to rot faster.
  • paulsam.0921PGulVzkzpaulsam.0921PGulVzkz Posts: 14
    my advice would be dont place the shed below ground level ..maybe a better idea would be raise the shed above the ground level with 4x2 treated timber frame ,then put a membrane under the base of the shed between the simple frame and the shed base ? that way any water penetration to the frame wont travel to the shed ? 
  • paulsam.0921PGulVzkzpaulsam.0921PGulVzkz Posts: 14
    rough sawn tannalised 4x2 would be around £8 per 8ft length 👍
  • NollieNollie Posts: 7,529
    A few inches isn’t much, but I would be inclined to raise the shed base up as paulsam says. In a similar situation I used railway sleepers bolted together to form a level frame about a foot wider than the footprint of the shed all round then laid sand and 60x40 concrete slabs within. I sized the box frame so the slabs fitted together exactly without having to cut them. This means there was a step up to the door, but I just haunched up the spoil from levelling the site to form a shallow ramp for wheeling in and out the lawnmower etc.
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
Sign In or Register to comment.